1. Field of the Invention
The present invention relates to a photoelectric transducing element to be used in the optical instruments, the electronics and so on, particularly with excellent transducing properties and an efficient space utilization when built in an instrument.
2. Description of the Prior Art
Quite recently, instruments in which the electronic circuit is built in are becoming more and more compact, while the packing density of the parts constituting such instruments are becoming larger and larger. This imposes restrictions on intermediary cables connecting these parts to each other which restrictions require that the cables should be lighter and more dense. Further, in order to raise the utilization efficiency of the space in the instruments, it is requested that the intermediary cables should be rich in flexibility, heat-resistive and could easily be connected to other parts.
In order to meet the above conditions, quite recently the intermediary cables (polyimide flexible wire) are constructed so that, on the polyimide film substrate, a conductor layer is patterned and further a polyimide film is provided on the conductor layer. Such polyimide flexible wire, which is excellent in flexibility and space utilization efficiency, is remarkably convenient for connecting the parts in a compact instrument to each other, whereby, however, if it is used too much, there exists a danger that the stray capacity of the wire will be increased or the electrical wire could easily be picked up from outside. Namely, the increase of the stray capacity of wire causes the response delay of the electrical circuit or decrease of the S/N ratio. This will often cause misoperations, which is undesirable. In order to eliminate such undesirable phenomena, the parts are integrated so as to cut the intermediary cables short, while the transmission parts of the low level signal as well as the connections of the high impedance circuitry are made as few as possible. However, the integration of the parts is limited technically and economically and it is difficult to integrate all the parts into a miniature type.
For example, the space itself in which the photoelectric transducing element of the light measuring part in the electronic circuit for controlling the exposure amount of the camera is contained has a limit and the photoelectric transducing element and the exposure control circuit parts should often be contained in separate spaces. Namely, the photoelectric transducing element and the electric circuit are contained in the spaces distant from each other, whereby the connection between them should be made by means of flexible intermediary cables.
It is necessary that the photoelectric transducing element to be used for the camera and so on should excel in sensitivity and weather resistance, cover the whole range of visible light and be quick in response. In order to meet such conditions, normally ceramic CdS and crystal silicon (hereinafter called C-Si) are used.
The photoelectric transducing portion of the photoelectric transducing element consisting of such materials is contained in a package, whose lead terminal is connected to the one end of the conductor of the flexible intermediary cable by heat press, soldering, ultrasonic bonding or the like, while the other end of the flexible cable is connected to the electronic circuit. If it is possible to form the photoelectric transducing element itself in a thin film, the element and the intermediary cable can be formed in one body on one member and in one plane, so that the bonding process between the above element and the cable is not necessary to simplify the manufacturing process. Accordingly, not only is the element itself light and thin so as to economize the space but also the misoperation is eliminated and, further, the properties are much improved. The thin film for constituting such photoelectric transducing element is normally formed by means of the vacuum metallization method, whereby Se, CdS and so on as materials for the photoelectric transducing material which can be manufactured by means of the metallization method cannot present the sensitivity, the weather resistance, the stability, the spectroscopic sensitivity and the light response satisfactorily by means of the conventional thin film forming method. Therefore, actually no construction of this formation has been brought into practice.